I got my century in this morning so I'm feeling good about the 400k next week. The only thing I'm a little concerned about is my butt which was very uncomfortable for the second half of the ride.
Interestingly, I wore clothes that I don't really like when I ride my DF that work well on the recumbent. On top I wore a loose fitting quarter-zip jersey, where I normally prefer fairly tight full-zips. On the bottom I wore Boure Elite bibs that have seams running down the front of the leg that chafe on the DF but are totally fine on the recumbent. I also find that I really prefer wearing gloves on the recumbent but normally don't on the DF unless its cold or raining.